Guilfoyle was born in Canton, Massachusetts. He attended Boston College High School and spoke at the 2005 commencement of the school's seniors. Guilfoyle enrolled at Lehigh University in 1968. He eventually graduated from Yale in 1977 with a major in economics. He studied at the Actor's Studio before building up a substantial theatrical reputation on and off Broadway, including 12 years with the Theatre Company of Boston, appearances in David Rabe's The Basic Training of Pavlo Hummel with Al Pacino and in David Mamet's Glengarry Glen Ross. He is often mistakenly referred to as the son of character actor Paul Guilfoyle but they are not related.

TRIVIA:

Participated in the Seattle Hockey Challenge in 2005 for the Ronald McDonald House Charity.

When he was 19 and doing his very first play in a small theater, a bus with 40 fans of 'Paul Guilfoyle (I)' (qv) (1902-1961) turned up, hoping to see their favorite actor. He had to explain to them that 'Paul Guilfoyle (I)' (qv) had been dead for 8 years.

Attended Lehigh University, class of 1972.

Has been in two movies with 'Harrison Ford (I)' (qv): _Air Force One (1997)_ (qv) and _Random Hearts (1999)_ (qv).

Often mistakenly referred to as the son of character actor 'Paul Guilfoyle (I)' (qv). They are not related.

Attended Boston College High School where he was a stand-out hockey player.